Telomers from ch=ch and icf2cf2i



3,016,407 TELOMERS FROM (XM CH AND ICF CFJ Neal 0. Brace, Wilmington, DeL, assignor to E. 1. du Pont de Nernonrs and Company, Wilmington, Bah, a corporation of Delaware No Drawing. Filed ept. 21, 1960, Ser. No. 57,388 6 Claims. (Cl. 260-653.1)

This invention is directed to the thermal addition of lCF CF l to ethylene. This reaction gives a series of products ICF CF (CH CH -I and wherein n is usually one or two but may be larger.

The thermal addition of perfluoroalkyl iodides C F I to ethylene was first disclosed by Haszeldine, J. Chem. Soc., 1949, 2856. 1,Z-diiodotetrafluoroethane has been known for some time [Raasch, US. 2,424,677, Coffman et al., J. Org. Chem, 14, 747 (1949)] but telomerization reactions of this compound with nonfluorinated olefins have never been reported.

it is an object of this invention to prepare products of structure iCF CF (CH CH I and wherein m and n are integers from 1 to about 5. It is a further object of this invention to provide a process for the thermal addition of ICF CF I to ethylene to produce the heretofore-described products.

These and other objects will become apparent in the following description and claims.

The products of the present invention are prepared by heating 1,2-diiodotetrafluoroeth-ane with ethylene under pressure, preferably in the presence of a small amount of tetrafiuoroethylene.

More specifically, the present invention is directed to compound-s of structure ICF CF (CH CH ,I and I CH CH CF CF CH CH I wherein m and n are integers of from one to about 5. The present invention also encompasses the process for preparing said compounds which process comprises heating 1,2-diiodotetrafiuoroethane with ethylene at a temperture of from about 180 C. to about 220 C. and a pressure of from about one atmosphere to about 700 atmospheres and recovering said compounds. A preferred embodiment is one wherein about 0.1 mole of tetrafluoroethylene per mole of ICF CF I is added to the reaction mixture.

Although it may seen obvious to extrapolate from C F l to ICF CF I so far as thermal additions to ethylene are concerned, it is not actually the case. The discoverers of ICF CF I have shown that the compound is not thermally stable; it decomposes to iodine and tetrafluoroethylene. The same effect is observed when the compound is exposed to ultraviolet light. The known instability would lead to the conclusion that ICF CF I would not be suitable as a telogen in radical additions to olefins such as ethylene. This conclusion is actually correct in two cases, the photochemical reaction and the reaction catalyzed by free radical generating compounds. In both cases, iodine and tetrafluoroethylene are formed. Small yields of products can be obtained in a few cases, none in others. It is surprising therefore that lCF CF l will undergo thermal addition to ethylene in spite of its known thermal instability.

The process of the present invention is carried out by heating a mixture of lCF CF I and ethylene at a temperature of from 180 to 220 C. under pressure. The concentration of ethylene present is determined by the eth- 3,016,407 Patented Jan. 9, 1952 ylene pressure, higher pressures meaning greater concentration. The reaction produces two types of products, i.e.,

Increasing ethylene pressure increases the amount of di and higher adducts formed at the expense of the mono adduct. Conversion of lCF CF l is not greatly affected.

A side reaction resulting from decomposition of ICF CF I to C F and I occurs leading to the formation of lCH CH l. This reaction is not serious, accounting at most for 10% of the ICF CF I. It is readily overcome by including a 10 mole percent excess of C 1 in the initial reaction mixture. Under these conditions little or no decomposition occurs. This is the preferred method of operation in both batch and continuous systems.

The reaction is best carried out at about 200 C. At temperatures below about 180 C., little or no reaction occurs while at temperatures much greater than 220 C., decomposition of ICF CF I becomes uncontrollable even in the presence of excess C F The diiodide reactant ICF CF I can be used as such in the reaction or it can be preformed by causing a mixture of I and C 1 to reactat about 150 C. before ethylene is added to the system. Each method has advantages and disadvantages. In a batch system, it is simpler, and preferred, to form ICF CF I from I and C 1 in the reaction vessel, eliminating the separate step of isolating TCF CF T. In a continuous system, preformed lCF CF- l must be used. It is not possible to form lCF CF l in situ in a one-stage continuous system since 1 and ethylene would, by necessity, be brought together resulting in the formation of considerable lCH Cl-L l, an undesirable byproduct. v

The following representative examples illustrate the present invention.

- Example 1 150 C. Then, the reaction mixture was heated at 200 C. for five hours [pressure 1750 p.s.i.g., decreased to 1250 p.s.i.g.]. The products [181 g.] were separated by distillation giving rcr cn cn cn r, B.P. 71/10 mm., 59/5.0 m-m., n 1.509. [25% conversion],

ICH CH CF CF CH CH I M.P. 112.5l13.5 C. [67% conversion] and ICH CH I, M.P. 8283 C. [510% conversion].

Analysis of lCF CF CH CH I.-Calcd. for C H F I C, 12.58; H, 1.05; F, 19.9; I, 66.6. Found: C, 12.4; H,

Analysis of lCH CH CF CF cl-l CH l.Calcd. for C H F I C, 17.58; H, 1.95; F, 18.5; I, 61.9. Found: C, 17.6; H, 2.0; F, 18.2; I, 61.7.

ICH CH I is a known compound [Beilstein, 4th ed., vol. I, p. 99, M.P. 8l-82 C.].

Example 2 Using the same procedure as Example 1, 180 g. [0.51 mole] of ICF CF I and 58 g. [2.07 mole] of ethylene were heated at C. for 1 hour [pressure 1450 p.s.i.g., no change]. The mixture Was then heated at 200 C. for 5 hours [pressure 1750 p.s.i.g., decreased to 1225 p.s.i.g.]. The product [178 g.] was separated as before giving lCF CF CH CH l [37% conversion],

ICH CH CF CBCH CH I [40% conversion], ICH CH I [6.4% conversion] and ICF CF I [4.5% recovery].

3 Example 3 A mixture of ICF CF I [180 g., 0.51 mole], ethylene [58 g., 2.07 mole] and tetrafiuoroethylene [5.0 g., 0.05 mole] was heated at 150 C. for 1 hour in a 400-ml. Hastelloy C shaker tube [pressure 1450 p.s.i.g., no change]. The mixture was then heated at 200 C. for five hours [pressure 1760 p.s.i.g., decreased to 1160 p.s.i.g.]. The product [192 g.] was separated as before giving TCF CP CH CH I [32.5% conversion],

[52.1% conversion], ICH CH I [1.3% conversion] and iCF CF I [14.1% recovery].

By comparing this example with Examples 1 and 2, it is readily apparent that the conversion to lCH cl-i i, the undesired by-product, has been considerably decreased.

Example 4 A mixture of iodine [127 g., 0.5 mole] and tetrafiuoroethylene [55 g., 0.55 mole] was placed in a 400-ml. Hastelloy shaker tube and heated at 150 C. for 0.5 hour [pressure 180 p.s.i.g., decreases to p.s.i.g.]. Then ethylene was compressed into the shaker tube to 2000 p.s.i.g. at 150 C. The mixture was then heated at 200 C. for 6.5 hours [pressure 2850 p.s.i.g., decreases to 1600 p.s.i.g.]. The product [225 g.] was separated as before giving iCF CF Ci-l Cfi i [9% conversion],

[79% conversion], I(CH CH CF CF CH CH 1 [6% conversion] and ICF CF 1 [15.3% recovery]. No ICH CH I was formed.

The product I(CH CH CF CF CH CH I had a M.P. of 67-68" C.

Anat'yis.-Calcd. for C F H I C, 21.9; H, 2.77; F, 17.4; I, 58.0. Found: C, 21.1; H, 3.0; F, 17.6; I, 56.3.

The following examples illustrate the attempted reaction using a free radical generating catalyst.

Example 5 A mixture of ICF CF I [90 g., 0.25 mole], ethylene [58 g., 2.07 mole] and di-tert-butyl peroxide [1.0 g.] Was heated for 8 hours at 140 C. [pressure 1250 p.s.i.g., no change]. The liquid product [88 g.] consisted of a 98% recovery of ICF CF I.

Similar experiments were carried out at 70 C. with 2,2-azobisisobutyronitrile using ICP CF I and hexene-l, hexyne-l and vinyl acetate. In each case, only the starting materials could be isolated. It is known that monoiodides react in high conversion with ethylene under these conditions.

When the reactions were repeated at 115120 C., ICF CF I decomposed. When the reaction with vinyl acetate and azonitrile Was repeated using an excess of tetrafiuoroethylene, no reaction occurred again.

The productsof the present invention are useful for a number of purposes. They can be converted to other difunctional derivatives such as alcohols by well-known reactions. They may also be converted to olefins which are useful in preparing fluorine containing polymers.

Example 6 l,6-diiodo-3,3,4,4-tetrafiuorohexane [41 g., 0.1 mole] and tri-n-butylamine [74.2 g., 0.4 mole] were heated on a flask attached to an efiicient fractional distillation col umn. The diolefin CH =CH(CF CH=CH RP. 72- 73 distilled from the reaction mixture at a 10/1 reflux ratio when the reaction temperature reached 200 C. [11.4 g., 75%]. A higher boiling product, B.P. 120- 125, 21;, 1.4171 [1.5 g.] was also isolated. 7

Analysis.-Calcd. for C T-1 R: C, 46.7; H, 3.9. Found: C, 46.9; H, 4.3.

The diolefin forms peroxides readily on standing.

It is apparent from the foregoing that the present process is a convenient and highly successful method for preparing compounds of type 1CF CF (CH CH I and I(CH CH CF CF (CH CH I and the products are valuable compounds as intermediates for a variety of useful compounds.

For exampie, the product ICH CH CF CF CH CH I is readily converted to the corresponding alcohol by reaction with silver acetate followed by hydrolysis using the procedures described by Park et alffor. C F CH CH 1, J. Org. Chem, 23, 1166 (1958.). The diols are then esterifie-d with perfiuorodicarboxylic acids to give polyesters. Such esters are useful high temperature lubricants (see Baranauckas et al., US. 2,911,444; Nov. 3, 1959, who describe lubricants and eiastomers prepared from HOCH (CF CH OI-I) Reaction of diiodide with silver ac-rylate gives the diacrylate ester CH 2 CH2 This monomer undergoes ready polymerization and can be used for crosslinking acrylate' polymers prepared from perliuo-roalkylacrylates such as CH =CHCO CH C F (polymers and copoiymers of this monomer are described by Anlbrecht et al., US. 2,642,416).

The dioiefin CH =CHCF CF CH=CH2 is readily oxidized by known methods, for example with potassium permanganate, to HO CCF CF CO H, a perfiuo-rodicar-boxylic acid, which may be used to prepare the polyester lubricants described above.

it is understood that the preceding examples may be varied Within the scope of one skilled in the art to produce the described results.

As many apparently widely different embodiments of this invention may be made without departing from the spirit and scope thereof, it is to be understood that this invention is not limited to the specific embodiments thereof except as defined in the appended claims.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A compound selected from the group consisting of those compounds having the structure and I(CH CH CF CF (CH CH l in which structures m and n are integers having a value within the range of from 1 to 5.

2. A process for preparing a compound selected from the group consisting of those compounds having the structure ICF CF (CH CH I and I CH CH CF C1? 2 CH CH I which process comprises heating 1,2-diiodotetr afluoroethane with ethylene at a temperature of from about C. to about 200 C. at a pressure of from about 1 to 700 atmospheres followed by recovering the compounds produced.

3. The process of claim 2 wherein about 0.1 mole of tetrafiuoroethylene per mole of lCF ClE l is added to the reaction mixture.

4. The compound ICF CF CH CH I.

5. The COIIIPOUHd 6. The compound ICH CH CF CF (CH CH I.

No r e es s te? 

1. A COMPOUND SELECTED FROM THE GROUP CONSISTING OF THOSE COMPOUNDS HAVING THE STRUCTURE 